(NaturalNews) The types of fat found in avocados and in olive oil boost levels of HDL ("good") cholesterol without raising levels of LDL ("bad") cholesterol, according to a study conducted by researchers from the University of Toronto and St. Michael's Hospital in Ontario, Canada, and published in the Canadian Medical Association Journal.

In fact, a special vegetarian diet with a dose of those special fats also reduced LDL levels as effectively as statin drugs.

Researchers placed 24 adults with moderately high cholesterol on a standard cholesterol-lowering diet (low in saturated fat) for one month. For the following month, participants were placed on a cholesterol-lowering vegetarian diet. Half were assigned to a vegetarian diet in which 13 percent of their carbohydrate calories were replaced by calories from monounsaturated fats.

At the end of the first month, both groups had reduced their LDL levels by roughly 20 percent, and at the end of the second month both had reduced them by 35 percent. In the monounsaturated oil group only, HDL levels had also increased by12 percent, and levels of the inflammation marker C-reactive protein had decreased.

"HDL cholesterol .... protects against free radical damage and has been proven to contribute to better control of the elevated blood triglyceride levels that are so common in diabetes," writes Michael T. Murray in his book Beat Diabetes Naturally.

"Some of these effects may be related to the ability of monounsaturated ... oil to improve insulin sensitivity. This effect has been seen not only in diabetics, but also in volunteers without diabetes."

Researcher David Jenkins said that the monounsaturated fat-heavy vegetarian diet "did exactly the thing you want," calling it promising for people "who want to give diet a serious try before resorting to medication."